System and method for automatically learning and maintaining IP address allocation topology

ABSTRACT

A topology map engine obtains, from a dynamic host control protocol relay device, a relayed request, of a client, for a dynamic host control protocol lease. The relayed request has at least one given IP address of the dynamic host control protocol relay device inserted therein. A search is made in a database for that IP address. If not found, dynamic host control protocol relay device information is obtained. This information includes: an identifier of the dynamic host control protocol relay device; and at least one network interface of the dynamic host control protocol relay device and any internet protocol addresses assigned to same. This information is obtained at the topology map engine and stored in the database.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation, under 37 CFR 1.53(b), of co-assignedU.S. patent application Ser. No. 13/631,103 of inventors Andrew Danforthet al., and claims the benefit thereof, said application Ser. No.13/631,103 having been filed on Sep. 28, 2012, and entitled “SYSTEM ANDMETHOD FOR AUTOMATICALLY LEARNING AND MAINTAINING IP ADDRESS ALLOCATIONTOPOLOGY.” The complete disclosure of the aforesaid application Ser. No.13/631,103 is expressly incorporated herein by reference in its entiretyfor all purposes.

FIELD OF THE INVENTION

The present invention relates generally to communications systems andmethods, and, more particularly, to Internet Protocol (IP) addressallocation techniques and the like.

BACKGROUND OF THE INVENTION

Until fairly recently, the cable network was predominantly a vehicle fordelivering entertainment. With the advent of the Internet and the risein demand for broadband two-way access, the cable industry began to seeknew ways of utilizing its existing plant. Pure coaxial (“coax”) cablenetworks were replaced with hybrid fiber networks (HFNs) using opticalfiber from the head end to the demarcation with the subscriber coax(usually at a fiber node). Currently, a content-based network, anon-limiting example of which is a cable television network, may affordaccess to a variety of services besides television, for example,broadband Internet access, telephone service, and the like.

One significant issue for a cable operator desiring to provide digitalservice is the configuration of its network. Designed for one-waydelivery of broadcast signals, the existing cable network topology wasoptimized for downstream (toward the subscriber) only service. Newequipment had to be added to the network to provide two-waycommunication. To reduce the cost of this equipment and to simplify theupgrade of the broadcast cable for two-way digital traffic, standardswere developed for a variety of new cable-based services. The first ofthese standards, the Data Over Cable System Interface Standard (DOCSIS®standard), was released in 1998. DOCSIS® establishes standards for cablemodems and supporting equipment. DOCSIS® (Data Over Cable ServiceInterface Specification) is a registered mark of Cable TelevisionLaboratories, Inc., 400 Centennial Parkway Louisville Colo. 80027, USA,and will be referred to for the remainder of this application in capitalletters, without the ® symbol, for convenience.

IP addresses are allocated in blocks known as subnets or prefixes on anetwork. These addresses are regularly allocated and moved as part ofnetwork growth and expansion. A cable modem termination system or CMTSis a piece of equipment typically located in a cable company's head endor hub site, and used to provide high speed data services, such as cableInternet or voice over Internet Protocol (VoIP), to cable subscribers. ACMTS provides many of the same functions provided by the digitalsubscriber line access multiplexer (DSLAM) in a digital subscriber line(DSL) system.

On a DOCSIS network, IP subnets are allocated on a per-CMTS basis.

SUMMARY OF THE INVENTION

Principles of the present invention provide a system and method forautomatically learning and maintaining IP address allocation topology.In one aspect, an exemplary method includes the step of obtaining, at atopology map engine, from a dynamic host control protocol relay device,a relayed request, of a client, for a dynamic host control protocollease. The relayed request has at least one given internet protocoladdress of the dynamic host control protocol relay device insertedtherein. A further step includes searching, in a database, for the atleast one given internet protocol address of the dynamic host controlprotocol relay device. A still further step includes, if the at leastone given internet protocol address of the dynamic host control protocolrelay device is not found in the database in the searching step,obtaining, at the topology map engine, from the dynamic host controlprotocol relay device, dynamic host control protocol relay deviceinformation. This information includes at least an identifier of thedynamic host control protocol relay device; at least one networkinterface of the dynamic host control protocol relay device; and anyinternet protocol address assigned to the at least one networkinterfaces of the dynamic host control protocol relay device. Thedynamic host control protocol relay device information is stored in thedatabase.

As used herein, “facilitating” an action includes performing the action,making the action easier, helping to carry the action out, or causingthe action to be performed. Thus, by way of example and not limitation,instructions executing on one processor might facilitate an actioncarried out by instructions executing on a remote processor, by sendingappropriate data or commands to cause or aid the action to be performed.For the avoidance of doubt, where an actor facilitates an action byother than performing the action, the action is nevertheless performedby some entity or combination of entities.

One or more embodiments of the invention or elements thereof can beimplemented in the form of an article of manufacture including a machinereadable medium that contains one or more programs which when executedimplement one or more method steps set forth herein; that is to say, acomputer program product including a tangible computer readablerecordable storage medium (or multiple such media) with computer usableprogram code for performing the method steps indicated. Furthermore, oneor more embodiments of the invention or elements thereof can beimplemented in the form of an apparatus (e.g., a topology map engineserver) including a memory and at least one processor that is coupled tothe memory and operative to perform, or facilitate performance of,exemplary method steps. Yet further, in another aspect, one or moreembodiments of the invention or elements thereof can be implemented inthe form of means for carrying out one or more of the method stepsdescribed herein; the means can include (i) specialized hardwaremodule(s), (ii) software module(s) stored in a tangiblecomputer-readable recordable storage medium (or multiple such media) andimplemented on a hardware processor, or (iii) a combination of (i) and(ii); any of (i)-(iii) implement the specific techniques set forthherein.

Techniques of the present invention can provide substantial beneficialtechnical effects. For example, one or more embodiments provide one ormore of the following technical benefits:

-   -   more accurate and complete knowledge of topology information;    -   ease in consolidation of topology information to make same        available to multiple other systems;    -   persistence of historical data;    -   real-time tracking of changes;    -   ability to discover statically allocated addresses (e.g., for        commercial customers)—can learn of a cable modem termination        system (CMTS) or the like by watching dynamic lease allocation,        and then during communication with the CMTS discover subnets and        prefixes that are allocated statically.

These and other features and advantages of the present invention willbecome apparent from the following detailed description of illustrativeembodiments thereof, which is to be read in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary embodiment of a system, withinwhich one or more aspects of the invention can be implemented;

FIG. 2 is a functional block diagram illustrating an exemplary hybridfiber-coaxial (HFC) divisional network configuration, useful within thesystem of FIG. 1;

FIG. 3 is a functional block diagram illustrating one exemplary HFCcable network head-end configuration, useful within the system of FIG.1;

FIG. 4 is a functional block diagram illustrating one exemplary localservice node configuration useful within the system of FIG. 1;

FIG. 5 is a functional block diagram of a premises network, including anexemplary centralized customer premises equipment (CPE) unit,interfacing with a head end such as that of FIG. 3;

FIG. 6 is a functional block diagram of an exemplary centralized CPEunit, useful within the system of FIG. 1;

FIG. 7 is a data flow chart and block diagram of an exemplary system,according to an aspect of the invention;

FIG. 8 is a block diagram of a computer system useful in connection withone or more aspects of the invention; and

FIG. 9 is an exemplary software architecture diagram showing onesoftware configuration for a topology map engine, according to an aspectof the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

IP-based data services may be provided over a variety of networks.Purely by way of example and not limitation, embodiments will be shownin the context of a cable multi-service operator (MSO) providing dataservices as well as entertainment services. However, one or moreembodiments are applicable in a variety of network contexts; forexample, fiber optic networks, wireless networks, DSL networks, and thelike; indeed, any IP network situation where an access device relaysDHCP traffic within a network that carries data (and optionally, otherinformation such as video programming; indeed, as discussed below, someembodiments are applicable to video content networks that are notcarrying separate Internet traffic but are utilizing DHCP requests inconnection with the transmission of video).

FIG. 1 shows an exemplary system 1000, according to an aspect of theinvention. System 1000 includes a regional data center (RDC) 1048, andone or more divisions, represented by division head ends 150. RDC 1048and head ends 150 are interconnected by a network 1046; by way ofexample and not limitation, a dense wavelength division multiplex (DWDM)network. Elements 1048, 150 on network 1046 may be operated, forexample, by or on behalf of a cable MSO, and may be interconnected witha global system of interconnected computer networks that use thestandardized Internet Protocol Suite (TCP/IP)(transfer controlprotocol/Internet protocol), commonly called the Internet 1002; forexample, via router 1008. In one or more non-limiting exemplaryembodiments, router 1008 is a point-of-presence (“POP”) router; forexample, of the kind available from Juniper Networks, Inc., Sunnyvale,Calif., USA.

Head ends 150 may each include a head end router (HER) 1091 whichinterfaces with network 1046. Head end routers 1091 are omitted fromFIGS. 2-5 below to avoid clutter.

RDC 1048 may include one or more provisioning servers (PS) 1050, one ormore Video Servers (VS) 1052, one or more content servers (CS) 1054, andone or more e-mail servers (ES) 1056. The same may be interconnected toone or more RDC routers (RR) 1060 by one or more multi-layer switches(MLS) 1058. RDC routers 1060 interconnect with network 1046.

FIG. 2 is a functional block diagram illustrating an exemplarycontent-based (e.g., hybrid fiber-coaxial (HFC)) divisional networkconfiguration, useful within the system of FIG. 1. See, for example, USPatent Publication 2006/0130107 of Gonder et al., entitled “Method andapparatus for high bandwidth data transmission in content-basednetworks,” the complete disclosure of which is expressly incorporated byreference herein in its entirety for all purposes. The variouscomponents of the network 100 include (i) one or more data andapplication origination points 102; (ii) one or more applicationdistribution servers 104; (iii) one or more video-on-demand (VOD)servers 105, and (v) consumer premises equipment or customer premisesequipment (CPE) 106. The distribution server(s) 104, VOD servers 105 andCPE(s) 106 are connected via a bearer (e.g., HFC) network 101. Servers104, 105 can be located in head end 150. A simple architecture is shownin FIG. 2 for illustrative brevity, although it will be recognized thatcomparable architectures with multiple origination points, distributionservers, VOD servers, and/or CPE devices (as well as different networktopologies) may be utilized consistent with embodiments of theinvention. For example, the head-end architecture of FIG. 3 (describedin greater detail below) may be used.

The data/application origination point 102 comprises any medium thatallows data and/or applications (such as a VOD-based or “Watch TV”application) to be transferred to a distribution server 104, forexample, over network 1102. This can include for example a third partydata source, application vendor website, compact disk read-only memory(CD-ROM), external network interface, mass storage device (e.g.,Redundant Arrays of Inexpensive Disks (RAID) system), etc. Suchtransference may be automatic, initiated upon the occurrence of one ormore specified events (such as the receipt of a request packet oracknowledgement (ACK)), performed manually, or accomplished in anynumber of other modes readily recognized by those of ordinary skill,given the teachings herein. For example, in one or more embodiments,network 1102 may correspond to network 1046 of FIG. 1, and the data andapplication origination point may be, for example, within RDC 1048 or onthe Internet 1002. Head end 150, HFC network 101, and CPEs 106 thusrepresent the divisions which were represented by division head ends 150in FIG. 1.

The application distribution server 104 comprises a computer systemwhere such applications can enter the network system. Distributionservers per se are well known in the networking arts, and accordinglynot described further herein.

The VOD server 105 comprises a computer system where on-demand contentcan be received from one or more of the aforementioned data sources 102and enter the network system. These servers may generate the contentlocally, or alternatively act as a gateway or intermediary from adistant source.

The CPE 106 includes any equipment in the “customers' premises” (orother appropriate locations) that can be accessed by a distributionserver 104 or a cable modem termination system 156 (discussed below withregard to FIG. 3). Non-limiting examples of CPE are set-top boxes andhigh-speed cable modems for providing high bandwidth Internet access inpremises such as homes and businesses.

Also included (for example, in head end 150) is a dynamic bandwidthallocation device (DBWAD) 1001 such as a global session resourcemanager, which is itself a non-limiting example of a session resourcemanager.

FIG. 3 is a functional block diagram illustrating one exemplary HFCcable network head-end configuration, useful within the system ofFIG. 1. As shown in FIG. 3, the head-end architecture 150 comprisestypical head-end components and services including billing module 152,subscriber management system (SMS) and CPE configuration managementmodule 3308, cable-modem termination system (CMTS) and out-of-band (OOB)system 156, as well as LAN(s) 158, 160 placing the various components indata communication with one another. In one or more embodiments, thereare multiple CMTSes 156-1 through 156-n. Each may be coupled to an HER1091, for example. See, e.g., FIGS. 1 and 2 of co-assigned U.S. Pat. No.7,792,963 of inventors Gould and Danforth, entitled METHOD TO BLOCKUNAUTHORIZED NETWORK TRAFFIC IN A CABLE DATA NETWORK, the completedisclosure of which is expressly incorporated herein by reference in itsentirety for all purposes.

It will be appreciated that while a bar or bus LAN topology isillustrated, any number of other arrangements (e.g., ring, star, etc.)may be used consistent with the invention. It will also be appreciatedthat the head-end configuration depicted in FIG. 3 is high-level,conceptual architecture and that each multi-service operator (MSO) mayhave multiple head-ends deployed using custom architectures.

The architecture 150 of FIG. 3 further includes amultiplexer/encrypter/modulator (MEM) 162 coupled to the HFC network 101adapted to “condition” content for transmission over the network. Thedistribution servers 104 are coupled to the LAN 160, which providesaccess to the MEM 162 and network 101 via one or more file servers 170.The VOD servers 105 are coupled to the LAN 158, although otherarchitectures may be employed (such as for example where the VOD serversare associated with a core switching device such as an 802.3z GigabitEthernet device; or the VOD servers could be coupled to LAN 160). Sinceinformation is typically carried across multiple channels, the head-endshould be adapted to acquire the information for the carried channelsfrom various sources. Typically, the channels being delivered from thehead-end 150 to the CPE 106 (“downstream”) are multiplexed together inthe head-end and sent to neighborhood hubs (refer to description of FIG.4) via a variety of interposed network components.

Content (e.g., audio, video, etc.) is provided in each downstream(in-band) channel associated with the relevant service group. (Note thatin the context of data communications, internet data is passed bothdownstream and upstream.) To communicate with the head-end orintermediary node (e.g., hub server), the CPE 106 may use theout-of-band (OOB) or DOCSIS® (Data Over Cable Service InterfaceSpecification) channels (registered mark of Cable TelevisionLaboratories, Inc., 400 Centennial Parkway Louisville Colo. 80027, USA)and associated protocols (e.g., DOCSIS 1.x, 2.0. or 3.0). The OpenCable™Application Platform (OCAP) 1.0, 2.0, 3.0 (and subsequent) specification(Cable Television laboratories Inc.) provides for exemplary networkingprotocols both downstream and upstream, although the invention is in noway limited to these approaches. All versions of the DOCSIS and OCAPspecifications are expressly incorporated herein by reference in theirentireties for all purposes.

Furthermore in this regard, DOCSIS is an internationaltelecommunications standard that permits the addition of high-speed datatransfer to an existing cable TV (CATV) system. It is employed by manycable television operators to provide Internet access (cable Internet)over their existing hybrid fiber-coaxial (HFC) infrastructure. Use ofDOCSIS to transmit data on an HFC system is one non-limiting exemplaryapplication of one or more embodiments. However, one or more embodimentsare generally applicable to IP transport of data, regardless of whatkind of network is employed.

It will also be recognized that multiple servers (broadcast, VOD, orotherwise) can be used, and disposed at two or more different locationsif desired, such as being part of different server “farms”. Thesemultiple servers can be used to feed one service group, or alternativelydifferent service groups. In a simple architecture, a single server isused to feed one or more service groups. In another variant, multipleservers located at the same location are used to feed one or moreservice groups. In yet another variant, multiple servers disposed atdifferent location are used to feed one or more service groups.

In some instances, material may also be obtained from a satellite feed1108; such material is demodulated and decrypted in block 1106 and fedto block 162. Conditional access system 157 may be provided for accesscontrol purposes. Network management system 1110 may provide appropriatemanagement functions. Note also that signals from MEM 162 and upstreamsignals from network 101 that have been demodulated and split in block1112 are fed to CMTS and OOB system 156.

Also included in FIG. 3 are a global session resource manager (GSRM)3302, a Mystro Application Server 104A, and a business management system154, all of which are coupled to LAN 158. GSRM 3302 is one specific formof a DBWAD 1001 and is a non-limiting example of a session resourcemanager.

An ISP DNS server could be located in the head-end as shown at 3303, butit can also be located in a variety of other places.

A DHCP server 3304 is preferably located in each regional data center1048 as seen in FIG. 1, but could also be located in different locations(e.g., in national data center 1049 or on LAN 158 or 160 in head end150). DHCP server 3304 is preferably coupled to national data center1049 via a backbone network similar to that described in connection withnetwork 1046. DHCP server 3304 preferably communicates with the CMTSes156 in each head end 150 over network 1046. National data center 1049can include an enterprise database 1051 to store a variety ofenterprise-wide (e.g., MSO-wide) data.

As shown in FIG. 4, the network 101 of FIGS. 2 and 3 comprises afiber/coax arrangement wherein the output of the MEM 162 of FIG. 3 istransferred to the optical domain (such as via an optical transceiver177 at the head-end 150 or further downstream). The optical domainsignals are then distributed over a fiber network to a fiber node 178,which further distributes the signals over a distribution network 180(typically coax) to a plurality of local servicing nodes 182. Thisprovides an effective 1-to-N expansion of the network at the localservice end. Each node 182 services a number of CPEs 106. Furtherreference may be had to US Patent Publication 2007/0217436 of Markley etal., entitled “Methods and apparatus for centralized content and datadelivery,” the complete disclosure of which is expressly incorporatedherein by reference in its entirety for all purposes. In one or moreembodiments, the CPE 106 includes a cable modem, such as aDOCSIS-compliant cable modem (DCCM).

Certain additional aspects of video or other content delivery will nowbe discussed for completeness, it being understood that embodiments ofthe invention have broad applicability to IP data communications andtransport. Again, delivery of data over a video (or other) contentnetwork is but one non-limiting example of a context where one or moreembodiments could be implemented. US Patent Publication 2003-0056217 ofPaul D. Brooks, entitled “Technique for Effectively Providing ProgramMaterial in a Cable Television System,” the complete disclosure of whichis expressly incorporated herein by reference for all purposes,describes one exemplary broadcast switched digital architecture,although it will be recognized by those of ordinary skill that otherapproaches and architectures may be substituted. In a cable televisionsystem in accordance with the Brooks invention, program materials aremade available to subscribers in a neighborhood on an as needed basis.Specifically, when a subscriber at a set-top terminal selects a programchannel to watch, the selection request is transmitted to a head end ofthe system. In response to such a request, a controller in the head enddetermines whether the material of the selected program channel has beenmade available to the neighborhood. If it has been made available, thecontroller identifies to the set-top terminal the carrier which iscarrying the requested program material, and to which the set-topterminal tunes to obtain the requested program material. Otherwise, thecontroller assigns an unused carrier to carry the requested programmaterial, and informs the set-top terminal of the identity of the newlyassigned carrier. The controller also retires those carriers assignedfor the program channels which are no longer watched by the subscribersin the neighborhood. Note that reference is made herein, for brevity, tofeatures of the “Brooks invention”—it should be understood that noinference should be drawn that such features are necessarily present inall claimed embodiments of Brooks. The Brooks invention is directed to atechnique for utilizing limited network bandwidth to distribute programmaterials to subscribers in a community access television (CATV) system.In accordance with the Brooks invention, the CATV system makes availableto subscribers selected program channels, as opposed to all of theprogram channels furnished by the system as in prior art. In the BrooksCATV system, the program channels are provided on an as needed basis,and are selected to serve the subscribers in the same neighborhoodrequesting those channels.

US Patent Publication 2010-0313236 of Albert Straub, entitled“TECHNIQUES FOR UPGRADING SOFTWARE IN A VIDEO CONTENT NETWORK,” thecomplete disclosure of which is expressly incorporated herein byreference for all purposes, provides additional details on theaforementioned dynamic bandwidth allocation device 1001.

US Patent Publication 2009-0248794 of William L. Helms, entitled “SYSTEMAND METHOD FOR CONTENT SHARING,” the complete disclosure of which isexpressly incorporated herein by reference for all purposes, providesadditional details on CPE in the form of a converged premises gatewaydevice. Related aspects are also disclosed in US Patent Publication2007-0217436 of Markley et al, entitled “METHODS AND APPARATUS FORCENTRALIZED CONTENT AND DATA DELIVERY,” the complete disclosure of whichis expressly incorporated herein by reference for all purposes.

Reference should now be had to FIG. 5, which presents a block diagram ofa premises network interfacing with a head end of an MSO or the like,providing Internet access. An exemplary advanced wireless gatewaycomprising CPE 106 is depicted as well. It is to be emphasized that thespecific form of CPE 106 shown in FIGS. 5 and 6 is exemplary andnon-limiting, and shows a number of optional features. Many other typesof CPE can be employed in one or more embodiments; for example, any DHCPclient 702 as described below, such as a cable modem, DSL modem, tabletcomputer, laptop computer, personal computer, network addresstranslation (NAT) router, computing device with a wireless card in awireless system, and the like.

CPE 106 includes an advanced wireless gateway which connects to a headend 150 or other hub of a network, such as a video content network of anMSO or the like. The head end is coupled also to an internet (e.g., theInternet) 208 which is located external to the head end 150, such as viaan Internet (IP) backbone or gateway (not shown).

The head end is in the illustrated embodiment coupled to multiplehouseholds or other premises, including the exemplary illustratedhousehold 240. In particular, the head end (for example, a cable modemtermination system 156 thereof) is coupled via the aforementioned HFCnetwork and local coaxial cable or fiber drop to the premises, includingthe consumer premises equipment (CPE) 106. The exemplary CPE 106 is insignal communication with any number of different devices including,e.g., a wired telephony unit 222, a Wi-Fi or other wireless-enabledphone 224, a Wi-Fi or other wireless-enabled laptop 226, a sessioninitiation protocol (SIP) phone, an H.323 terminal or gateway, etc.Additionally, the CPE 106 is also coupled to a digital video recorder(DVR) 228 (e.g., over coax), in turn coupled to television 234 via awired or wireless interface (e.g., cabling, PAN or 802.15 UWB micro-net,etc.). CPE 106 is also in communication with a network (here, anEthernet network compliant with IEEE Std. 802.3, although any number ofother network protocols and topologies could be used) on which is apersonal computer (PC) 232.

Other non-limiting exemplary devices that CPE 106 may communicate withinclude a printer 294; for example over a universal plug and play (UPnP)interface, and/or a game console 292; for example, over a multimediaover coax alliance (MoCA) interface.

In some instances, CPE 106 is also in signal communication with one ormore roaming devices, generally represented by block 290.

A “home LAN” (HLAN) is created in the exemplary embodiment, which mayinclude for example the network formed over the installed coaxialcabling in the premises, the Wi-Fi network, and so forth.

During operation, the CPE 106 exchanges signals with the head end overthe interposed coax (and/or other, e.g., fiber) bearer medium. Thesignals include e.g., Internet traffic (IPv4 or IPv6), digitalprogramming and other digital signaling or content such as digital(packet-based; e.g., VoIP) telephone service. The CPE 106 then exchangesthis digital information after demodulation and any decryption (and anydemultiplexing) to the particular system(s) to which it is directed oraddressed. For example, in one embodiment, a MAC address or IP addresscan be used as the basis of directing traffic within the client-sideenvironment 240.

Any number of different data flows may occur within the network depictedin FIG. 5. For example, the CPE 106 may exchange digital telephonesignals from the head end which are further exchanged with the telephoneunit 222, the Wi-Fi phone 224, or one or more roaming devices 290. Thedigital telephone signals may be IP-based such as Voice-over-IP (VoIP),or may utilize another protocol or transport mechanism. The well knownsession initiation protocol (SIP) may be used, for example, in thecontext of a “SIP phone” for making multi-media calls. The network mayalso interface with a cellular or other wireless system, such as forexample a 3G IMS (IP multimedia subsystem) system, in order to providemultimedia calls between a user or consumer in the household domain 240(e.g., using a SIP phone or H.323 terminal) and a mobile 3G telephone orpersonal media device (PMD) user via that user's radio access network(RAN).

The CPE 106 may also exchange Internet traffic (e.g., TCP/IP and otherpackets) with the head end 150 which is further exchanged with the Wi-Filaptop 226, the PC 232, one or more roaming devices 290, or otherdevice. CPE 106 may also receive digital programming that is forwardedto the DVR 228 or to the television 234. Programming requests and othercontrol information may be received by the CPE 106 and forwarded to thehead end as well for appropriate handling.

FIG. 6 is a block diagram of one exemplary embodiment of the CPE 106 ofFIG. 5. The exemplary CPE 106 includes an RF front end 301, Wi-Fiinterface 302, video interface 316, “Plug n′ Play” (PnP) interface 318(for example, a UPnP interface) and Ethernet interface 304, eachdirectly or indirectly coupled to a bus 312. In some cases, Wi-Fiinterface 302 comprises a single wireless access point (WAP) runningmultiple (“m”) service set identifiers (SSIDs). In some cases, multipleSSIDs, which could represent different applications, are served from acommon WAP. For example, SSID 1 is for the home user, while SSID 2 maybe for a managed security service, SSID 3 may be a managed homenetworking service, SSID 4 may be a hot spot, and so on. Each of theseis on a separate IP subnetwork for security, accounting, and policyreasons. The microprocessor 306, storage unit 308, plain old telephoneservice (POTS)/public switched telephone network (PSTN) interface 314,and memory unit 310 are also coupled to the exemplary bus 312, as is asuitable MoCA interface 391. The memory unit 310 typically comprises arandom access memory (RAM) and storage unit 308 typically comprises ahard disk drive, an optical drive (e.g., CD-ROM or DVD), NAND flashmemory, RAID (redundant array of inexpensive disks) configuration, orsome combination thereof.

The illustrated CPE 106 can assume literally any discrete form factor,including those adapted for desktop, floor-standing, or wall-mounteduse, or alternatively may be integrated in whole or part (e.g., on acommon functional basis) with other devices if desired.

Again, it is to be emphasized that every embodiment need not necessarilyhave all the elements shown in FIG. 6—as noted, the specific form of CPE106 shown in FIGS. 5 and 6 is exemplary and non-limiting, and shows anumber of optional features. Yet again, many other types of CPE can beemployed in one or more embodiments; for example, any DHCP client 702 asdescribed below, such as a cable modem, DSL modem, tablet computer,laptop computer, personal computer, network address translation (NAT)router, computing device with a wireless card in a wireless system, andthe like.

It will be recognized that while a linear or centralized busarchitecture is shown as the basis of the exemplary embodiment of FIG.6, other bus architectures and topologies may be used. For example, adistributed or multi-stage bus architecture may be employed. Similarly,a “fabric” or other mechanism (e.g., crossbar switch, RAPIDIO interface,non-blocking matrix, TDMA or multiplexed system, etc.) may be used asthe basis of at least some of the internal bus communications within thedevice. Furthermore, many if not all of the foregoing functions may beintegrated into one or more integrated circuit (IC) devices in the formof an ASIC or “system-on-a-chip” (SoC). Myriad other architectures wellknown to those in the data processing and computer arts may accordinglybe employed.

Yet again, it will also be recognized that the CPE configuration shownis essentially for illustrative purposes, and various otherconfigurations of the CPE 106 are consistent with other embodiments ofthe invention. For example, the CPE 106 in FIG. 6 may not include all ofthe elements shown, and/or may include additional elements andinterfaces such as for example an interface for the HomePlug A/Vstandard which transmits digital data over power lines, a PAN (e.g.,802.15), Bluetooth, or other short-range wireless interface forlocalized data communication, etc.

A suitable number of standard 10/100/1000 Base T Ethernet ports for thepurpose of a Home LAN connection are provided in the exemplary device ofFIG. 6; however, it will be appreciated that other rates (e.g., GigabitEthernet or 10-Gig-E) and local networking protocols (e.g., MoCA, USB,etc.) may be used. These interfaces may be serviced via a WLANinterface, wired RJ-45 ports, or otherwise. The CPE 106 can also includea plurality of RJ-11 ports for telephony interface, as well as aplurality of USB (e.g., USB 2.0) ports, and IEEE-1394 (Firewire) ports.S-video and other signal interfaces may also be provided if desired.

During operation of the CPE 106, software located in the storage unit308 is run on the microprocessor 306 using the memory unit 310 (e.g., aprogram memory within or external to the microprocessor). The softwarecontrols the operation of the other components of the system, andprovides various other functions within the CPE. Other systemsoftware/firmware may also be externally reprogrammed, such as using adownload and reprogramming of the contents of the flash memory,replacement of files on the storage device or within other non-volatilestorage, etc. This allows for remote reprogramming or reconfiguration ofthe CPE 106 by the MSO or other network agent.

The RF front end 301 of the exemplary embodiment comprises a cable modemof the type known in the art. In some cases, the CPE just includes thecable modem and omits the optional features. Content or data normallystreamed over the cable modem can be received and distributed by the CPE106, such as for example packetized video (e.g., IPTV). The digital dataexchanged using RF front end 301 includes IP or other packetizedprotocol traffic that provides access to internet service. As is wellknown in cable modem technology, such data may be streamed over one ormore dedicated QAMs resident on the HFC bearer medium, or evenmultiplexed or otherwise combined with QAMs allocated for contentdelivery, etc. The packetized (e.g., IP) traffic received by the CPE 106may then be exchanged with other digital systems in the localenvironment 240 (or outside this environment by way of a gateway orportal) via, e.g. the Wi-Fi interface 302, Ethernet interface 304 orplug-and-play (PnP) interface 318.

It will be appreciated, however, that the RF front end 301 of the CPEmay comprise (either in addition to or in place of the cable modem) atraditional video RF front end 301 (e.g., tuner) adapted to receivevideo signals over, e.g., a QAM. For example, one exemplary embodimentof the RF front end 301 comprises one or more tuners, a demodulator,decryption module, and demultiplexer of the type well known in the art,although other configurations may be used. Some embodiments areapplicable to video content networks that are not carrying separateInternet traffic but are utilizing DHCP requests in connection with thetransmission of video. Additionally, the RF front end 301 modulates,encrypts/multiplexes as required, and transmits digital information forreceipt by upstream entities such as the CMTS or a network server.Digital data transmitted via the RF front end 301 may include, forexample, MPEG-2 encoded programming data that is forwarded to atelevision monitor via the video interface 316. Programming data mayalso be stored on the CPE storage unit 308 for later distribution by wayof the video interface 316, or using the Wi-Fi interface 302, Ethernetinterface 304, Firewire (IEEE Std 1394), USB/USB2, or any number ofother such options.

Other devices such as portable music players (e.g., MP3 audio players)may be coupled to the CPE 106 via any number of different interfaces,and music and other media files downloaded for portable use and viewing.

In some instances, the CPE 106 includes a DOCSIS cable modem fordelivery of traditional broadband Internet services. This connection canbe shared by all Internet devices in the premises 240; e.g. Internetprotocol television (IPTV) devices, PCs, laptops, etc., as well as byroaming devices 290. In addition, the CPE 106 can be remotely managed(such as from the head end 150, or another remote network agent) tosupport appropriate IP services.

In some instances the CPE 106 also creates a home Local Area Network(LAN) utilizing the existing coaxial cable in the home. For example, anEthernet-over-coax based technology allows services to be delivered toother devices in the home utilizing a frequency outside (e.g., above)the traditional cable service delivery frequencies. For example,frequencies on the order of 1150 MHz could be used to deliver data andapplications to other devices in the home such as PCs, PMDs, mediaextenders and set-top boxes. The coaxial network is merely the bearer;devices on the network utilize Ethernet or other comparable networkingprotocols over this bearer.

The exemplary CPE 106 shown in FIGS. 5 and 6 acts as a Wi-Fi accesspoint (AP), thereby allowing Wi-Fi enabled devices to connect to thehome network and access Internet, media, and other resources on thenetwork. This functionality can be omitted in one or more embodiments.

In one embodiment, Wi-Fi interface 302 comprises a single wirelessaccess point (WAP) running multiple (“m”) service set identifiers(SSIDs). One or more SSIDs can be set aside for the home network whileone or more SSIDs can be set aside for roaming devices 290.

A premises gateway software management package (application) is alsoprovided to control, configure, monitor and provision the CPE 106 fromthe cable head-end 150 or other remote network node via the cable modem(DOCSIS) interface. This control allows a remote user to configure andmonitor the CPE 106 and home network.

The MoCA interface 391 can be configured, for example, in accordancewith the MoCA 1.0, 1.1, or 2.0 specifications.

As discussed above, the optional Wi-Fi wireless interface 302 is, insome instances, also configured to provide a plurality of unique serviceset identifiers (SSIDs) simultaneously. These SSIDs are configurable(locally or remotely), such as via a web page.

In addition to “broadcast” content (e.g., video programming), thesystems of FIGS. 1-6 also deliver Internet data services using theInternet protocol (IP), although other protocols and transportmechanisms of the type well known in the digital communication art maybe substituted. The IP packets are typically transmitted on RF channelsthat are different that the RF channels used for the broadcast video andaudio programming, although this is not a requirement. The CPE 106 areeach configured to monitor the particular assigned RF channel (such asvia a port or socket ID/address, or other such mechanism) for IP packetsintended for the subscriber premises/address that they serve.

As noted, IP addresses are allocated in blocks known as subnets orprefixes on a network. These addresses are regularly allocated and movedas part of network growth and expansion. On a DOCSIS network, IP subnetsare allocated on a per-CMTS basis.

One or more embodiments advantageously provide techniques to maintain anaccurate enterprise-wide subnet to CMTS IP address allocation map.

One or more embodiments provide an automated mechanism for IP subnetdiscovery based upon observing dynamic host control protocol (DHCP)traffic originating from clients. When a CMTS relays a client DHCPrequest, it includes one of its own IP addresses in the forwardedpacket. This IP address is used to trigger discovery of all IP subnetsconfigured on the CMTS using Simple Network Management Protocol (SNMP).This approach works with DHCPv4 and DHCPv6 as they both include a CMTSaddress in the relayed message.

The topology discovery service preferably runs on a server in nationaldata center 1049 while a lightweight agent preferably runs on each DHCPserver 3304 in each regional data center 1048 and forwards the DHCPinformation up to the national topology discovery service. This nationalservice in turn carries out topology discovery and periodicallyinterrogates every CMTS 156-1 through 156-n it has learned about for IPsubnet information. The topology service does not require apreconfigured list of CMTS addresses as it automatically learns them byobserving traffic they forward. This information is aggregated in acentralized database (for example, enterprise database 1051 in thenational data center 1049) and made available to any interested systems.By observing DHCP messaging and communicating directly with CMTSes, oneor more embodiments require no human intervention and are guaranteed tobe accurate.

One or more embodiments are useful, for example, in the context of cloneprevention and/or theft of service; BSS Tools (billing and businesssupport system); and/or a PCMM (PacketCable™ Multimedia Specification)Policy Server (mark of Cable Television Laboratories, Inc., Louisville,Colo., USA). The PacketCable™ Specification-Multimedia Specification,PKT-SP-MM-106-110629, of Cable Television Laboratories, Inc., isexpressly incorporated herein by reference in its entirety for allpurposes.

One or more embodiments advantageously do not require manualconfiguration of all CMTS IP addresses. One or more embodimentsadvantageously automatically discover CMTSes by observing DHCP trafficthey forward. This triggers an automatic IP subnet discovery process.

There are many reasons why it is useful to know all the IP addressesthat are managed or provisioned on a CMTS 156. High-speed data providers(e.g., cable providers) typically have a CMTS and have a number of IPsubnets that are configured on that CMTS. The subnets are used todynamically assign IP addresses to customers that are served by the sameCMTS. The IP blocks are configured on the CMTS and also configured onthe DHCP servers 3304. Depending upon what back office tools areavailable, some operators may have automated provisioning of the IPblocks carried out in the CMTS 156. Other operators may not have acentral place they can go to and request all the IP subnet to CMTStopology information (e.g., in map or table form). One or moreembodiments automatically build such a map.

Again, one or more embodiments are applicable in a variety of networksituations and are not limited to the specific HFC embodiment used forillustrative purposes. In one or more embodiments, all theaforementioned IP blocks are assigned to a given CMTS. The CMTS “sees” apacket come up from a customer with an IP address in it. In one or moreembodiments, based on seeing traffic from a given IP address, adetermination is made as to what CMTS is providing service for theparticular customer. One or more embodiments are configured to map an IPaddress back to an IP network which is then assigned to a CMTS.

In one or more embodiments, the IP traffic in question is coming into aserver of an MSO or the like, originating from one of the MSO'scustomers, and the MSO needs to know what CMTS is providing the servicefor that customer. All that is available to the MSO to make thatassociation is the IP address that the packet came from. Thus, in one ormore embodiments, the packet in question is not necessarily from trafficcoming from the world (e.g., Internet 1002). One or more embodimentsadvantageously allow mapping a customer's IP address to thecorresponding CMTS 156.

In one or more embodiments, the MSO's customer (or a party purporting tobe a customer) could be attempting to access the MSO's server for avariety of reasons; for example, legitimate reasons (access to a PCMMserver) or illegitimate reasons such as an attempt to clone cable modemsor the like.

In one non-limiting exemplary use case, a customer desires some kind ofservice change; for example, the customer desires to try out a higherspeed tier or the like. The MSO needs to know what CMTS the customer isbehind so the MSO can access the appropriate CMTS and tell the CMTS toapply the appropriate policy (e.g., for the desired upgraded servicetier). Normally, in current systems, when the customer accesses theparticular web server or the like, the MSO does not know what CMTS thecustomer behind—all the MSO has is the customer's information and the IPaddress the customer is coming from. The MSO, in current systems,typically does not know what cable modem the customer is behind or whatCMTS the customer is behind. That is to say, currently, the MSOtypically does not know all of the topology information regarding theactual network between the MSO and the customer.

Thus, in one exemplary use case, an MSO's customer desires to upgradehis or her service. He or she accesses, e.g., a web site that is run bythe MSO and that allows him or her to manage his or her account. He orshe wants to upgrade to a faster service. All the MSO knows is whatcomputer he or she is on at that moment but not where he or she is inthe MSO's network, or what cable modem he or she is connected to.Advantageously, one or more embodiments are configured to dynamicallydiscover where in the MSO's network (e.g., in terms of the DOCSIS sideof the network) the customer is—what equipment the customer is behind(i.e., what is the path between the customer and the MSO).

In one or more embodiments, a table or similar data structure ispopulated over time while the MSO operates the network. Then, whensubscribers come and try to carry out customer service activity or thelike, the MSO has the table or similar data structure pre-built in adatabase.

One or more embodiments of the invention are applicable in a widevariety of scenarios. Purely by way of example and not limitation, oneor more embodiments could be employed to determine the addresses ofcable modems associated with a given cable modem termination system, forexample, to assist in implementing aspects of the aforementioned U.S.Pat. No. 7,792,963; to implement anti cable-modem cloning functionality;to block unauthorized network traffic to facilitate consumption-basedbilling; and the like. Furthermore with regard to clone prevention, U.S.Pat. No. 7,895,665 to Gould et al. is entitled “System and method fordetecting and reporting cable network devices with duplicate mediaaccess control addresses”; the complete disclosure of same is expresslyincorporated herein by reference in its entirety for all purposes. Oneor more embodiments disclosed in this Gould '665 patent utilize cablemodem MAC address/giaddr tuple data (gateway interface address or“giaddr” identifies the CMTS through which the cable modem iscommunicating). Advantageously, one or more embodiments disclosed hereincan be used to discover a permanent identifier of the CMTS or other DHCPrelay for use as the giaddr in one or more techniques of the Gould '665patent, thus basing its techniques on physical topology information notdependent on what version of the Internet protocol is being employed.

Thus far, exemplary embodiments have been described in the context of aCMTS in an HFC network. However, one or more embodiments can beimplemented in a variety of different kinds of networks, examples ofwhich have been set forth elsewhere herein. One or more embodimentsemploy SNMP (simple network management protocol) to send and obtain datafrom manageable network devices. Using SNMP, it is possible tocommunicate with the CMTS or the like and inquire as to all of the IPnetworks that the CMTS has configured. One or more embodiments areconfigured to learn of all the CMTSes that are on the network. One ormore embodiments observe DHCP traffic being relayed from the CMTS. Thus,in one or more embodiments, DHCP is the protocol used to dynamicallyallocate addresses to customers and devices on the network. The DHCPmessages are observed. Inside of each of the DHCP messages, there isinformation that includes one of the IP addresses that the CMTS isconfigured to use. Thus, one or more embodiments obtain that IP addressout of the DHCP message and then employ that IP address to communicatewith the CMTS and discover all of its configured IP addresses.

In some instances, an IP address is obtained and is looked up in anexisting table to see if it is known. If not known, the above-discussedSNMP communication is initiated. Periodic refreshing can be carried out;i.e., while the national system receives a feed of all the leasetransactions that are occurring, at the same time, it canopportunistically query the CMTSes that it is aware of to potentiallylearn about changes before it sees a lease request. That is to say,outside of being triggered by a lease request, once the national systemhas learned of a CMTS it can periodically query that CMTS.

Reference should now be had to FIG. 7, which depicts a non-limitingexemplary embodiment. As noted above, one or more embodiments are notlimited to CMTSes, but are generally applicable wherever a dynamic hostcontrol protocol relay process is carried out. This aspect isgenerically referred to as a DHCP Relay 704; non-limiting examplesinclude a CMTS 156, a DSLAM (DSL aggregator), or some other sort ofrouter.

Client 702 (for example, the cable modem in CPE 106) requests a DHCPlease from DHCP relay 704. The DHCP Relay 704 relays the request to DHCPserver 708 via network 706. When relaying the request, the DHCP Relay704 inserts its own IP address in the packet. In a non-limiting example,DHCP Relay 704 is CMTS 156 in head end 150, network 706 is network 1046,DHCP server 708 is DHCP server 3304 in regional data center 1048, andclient 702 is connected to the DHCP Relay 704 (which, in this case, isCMTS 156) via HFC network 101. Client 702 may reside, for example, inpremises; engine 712 and database 714 may reside, for example, innational data center 1049. Database 714 may be part of enterprisedatabase 1051 or may be a stand-alone database.

A lease forwarder component 710 on DHCP server 708 sends the DHCP leasedetails to an aggregator (e.g., into database 714 associated withtopology map engine 712). Component 710 includes logic to pass therequests to engine 712. Topology map engine 712 examines the DHCP leaseand extracts the IP address of the DHCP relay 704, which was insertedinto the packet by DHCP Relay 704 when it relayed the DHCP lease requestfrom client 702 to DHCP server 708.

Topology engine 712 searches the associated database 714 for the IPaddress of the DHCP Relay 704. If the DHCP Relay's IP address is notknown, discovery of the DHCP Relay begins. If the DHCP Relay's IPaddress is known, database 714 is searched for the subnet containing theIP address of client 702. If the subnet is not known, the local datamust be out of date, so discovery of the DHCP Relay is performed again.

One exemplary discovery process includes performing SNMP queries againstthe IP address of the DHCP Relay 704, as indicated by the notation“SNMP” next to the dotted line running from the topology map engine 712to the DHCP Relay 704. The SNMP queries determine a unique identifierfor the DHCP relay (which could include hostname, serial number, orloopback IP address), all network interfaces, and the IP addressesassigned to those interfaces.

Once a DHCP Relay 704 is known to the system, engine 712 preferablyperiodically re-polls the DHCP Relay 704 to detect if any changes weremade. The topology engine 712 could, optionally, also maintain ahistorical view of IP address allocations including the first and/orlast time a subnet was seen on a particular DHCP Relay 704, and whatnetwork interface of DHCP Relay 704 it was configured on.

Referring to FIG. 9, in some instances, topology map engine 712 includeslease request receiver module 791, interrogator module 793, optionallyscheduler module 795, and change determining module 797.

Given the discussion thus far, it will be appreciated that, in generalterms, an exemplary method, according to an aspect of the invention,includes the step of obtaining, at a topology map engine 712, from adynamic host control protocol relay device 704, a relayed request, of aclient 702, for a dynamic host control protocol lease. The engine 712may run, for example, on one or more servers in the national data center1049. Database 714 is on, or accessible to, these national data centerserver(s). This step can be carried out, for example, by module 791executing on one or more hardware processors of a server in nationaldata center 1049.

The relayed request has an internet protocol address of the dynamic hostcontrol protocol relay device 704 inserted therein. The relay device mayin general have one or more IP addresses.

A further step includes searching, in a database 714, for the at leastone given internet protocol address of the dynamic host control protocolrelay device 704. This step can also be carried out, for example, bymodule 791 executing on one or more hardware processors of a server innational data center 1049.

A still further step includes, if the at least one given internetprotocol address of the dynamic host control protocol relay device 704is not found in the database 714 in the searching step, obtaining, atthe topology map engine 712, from the dynamic host control protocolrelay device 704, dynamic host control protocol relay deviceinformation. Such information includes an identifier of the dynamic hostcontrol protocol relay device; and at least one network interface of thedynamic host control protocol relay device and any internet protocoladdress assigned to the at least one network interface of the dynamichost control protocol relay device.

An even further step includes storing the dynamic host control protocolrelay device information in the database 714. The steps of obtaining andstoring the DHCP relay device information can also be carried out, forexample, by module 791 executing on one or more hardware processors of aserver in national data center 1049.

The aforementioned identifier is preferably a permanent identifier,discussed further below. One non-limiting example is a chassis numberassociating a modem to a CMTS chassis (i.e. association is based on thename of the CMTS rather than the specific IP addresses it has). Onenon-limiting exemplary use case uses topology information to make adetermination as to what set of IP addresses is on a given CMTS “A”;i.e., CMTS “A” has certain IPv4 addresses and certain IPv6 addresses.Thus, when making the determination as to whether a given cable modem iscloned, rather than looking at specific IPv4 addresses, which are onlyrelevant in the context of IPv4, topology information obtained inaccordance with one or more embodiments of the invention is utilized. Inthis way, it does not matter whether the customer is an IPv4 customer oran IPv6 customer; the MSO can take the topology information and map itto the name of the CMTS and then make all the determinations using theCMTS's name rather than the IP address(es). Please refer to the abovediscussion of modem MAC address/giaddr tuple data in the Gould '665patent wherein one or more aspects of the present invention can be usedto determine a permanent identifier of the CMTS for use as the giaddr.

In one or more embodiments, if the at least one given internet protocoladdress of the dynamic host control protocol relay device 704 is notfound in the database 714 in the searching step, a query is sent, fromthe topology map engine 712, back to the dynamic host control protocolrelay device 704, for the dynamic host control protocol relay deviceinformation. Such information preferably includes the permanentidentifier of the dynamic host control protocol relay device; allnetwork interfaces of the dynamic host control protocol relay device;and all of the internet protocol addresses assigned to the networkinterfaces of the dynamic host control protocol relay device. In thisregard, “all” the IP addresses could include one or more such addresses(i.e. the IP address in the relayed request and optionally one or moreadditional IP addresses). Optionally, prefixes not allocated using DHCPcan also be included. Preferably, even if the DHCP relay device only hasa single IP address, a request is still made for “all” the addresses sothat it can be determined that there is only the single address.

This query-sending step can be carried out, for example, by module 793executing on one or more hardware processors of a server in nationaldata center 1049.

In some cases, the sending of the query, from the topology map engine,back to the dynamic host control protocol relay device, for the dynamichost control protocol relay device information, includes sending thequery as a simple network management protocol (SNMP) message.

The relayed request can be an Internet Protocol Version 4 (IPv4) requestor an Internet Protocol Version 6 (IPv6) request; furthermore, bothkinds of requests can be handled by one or more embodiments.

In some cases, additional steps include repeating the steps of obtainingthe relayed request, and searching in the database, for a relayedrequest from another, known, dynamic host control protocol relay devicerelaying a request of another client; and, responsive to at least onegiven internet protocol address of the known dynamic host controlprotocol relay device being found in the database in the repeatedsearching step, searching the database 714 for a subnet containing anaddress of the other client.

In such cases, responsive to the subnet not being found in the database,a further step can include rediscovering the known, dynamic host controlprotocol relay device.

Further, some instances include periodically re-polling the dynamic hostcontrol protocol relay device 704; and, in the event of a changedetected by the re-polling, storing updated dynamic host controlprotocol relay device information in the database 714. The re-pollingcould be initiated, for example, by module 795 executing on one or morehardware processors of a server in national data center 1049; the changedetection could be carried out, for example, by module 797 executing onone or more hardware processors of a server in national data center1049.

The permanent identifier of the dynamic host control protocol relaydevice could include a hostname, a serial number, a loopback internetprotocol address, a chassis number, or the like. A loopback internetprotocol address is a persistent static IP address for a DHCP relay thatis used for management purposes.

Furthermore, as noted, the dynamic host control protocol relay devicecan be, for example, a cable modem termination system or a digitalsubscriber line access multiplexer (D SLAM).

In some cases, the steps are repeated for a plurality of additionalrelayed requests from a plurality of additional dynamic host controlprotocol relay devices; and, based on the repeated steps, a historicallog is maintained. For example, the log may include information such asfirst and/or last time a subnet is on a particular relay 704, and whatnetwork interface of the relay 704 the subnet was configured on.

In one or more embodiments, in the steps of querying for and obtainingthe dynamic host control protocol relay information, the internetprotocol addresses assigned to the network interfaces of the dynamichost control protocol relay device include the at least one giveninternet protocol address obtained in the relayed request, and at leastone additional statically allocated internet protocol address. That isto say, one or more embodiments provide the ability to discoverstatically allocated addresses (e.g., for commercial customers). Forexample, the topology map engine can learn of a CMTS by observingdynamic lease allocation, but can also discover subnets and prefixesthat are allocated statically, via communication with the CMTS.

System and Article of Manufacture Details

The invention can employ hardware aspects or a combination of hardwareand software aspects. Software includes but is not limited to firmware,resident software, microcode, etc. One or more embodiments of theinvention or elements thereof can be implemented in the form of anarticle of manufacture including a machine readable medium that containsone or more programs which when executed implement such step(s); that isto say, a computer program product including a tangible computerreadable recordable storage medium (or multiple such media) withcomputer usable program code configured to implement the method stepsindicated, when run on one or more processors. Furthermore, one or moreembodiments of the invention or elements thereof can be implemented inthe form of an apparatus including a memory and at least one processorthat is coupled to the memory and operative to perform, or facilitateperformance of, exemplary method steps.

Yet further, in another aspect, one or more embodiments of the inventionor elements thereof can be implemented in the form of means for carryingout one or more of the method steps described herein; the means caninclude (i) specialized hardware module(s), (ii) software module(s)executing on one or more general purpose or specialized hardwareprocessors, or (iii) a combination of (i) and (ii); any of (i)-(iii)implement the specific techniques set forth herein, and the softwaremodules are stored in a tangible computer-readable recordable storagemedium (or multiple such media). Appropriate interconnections via bus,network, and the like can also be included.

FIG. 8 is a block diagram of a system 800 that can implement at leastsome aspects of the invention, and is representative, for example, ofone or more of the servers shown in the figures. The processor, memory,and process are also representative of aspects of the functionality ofthe elements 702, 704, 708, 712 in FIG. 7. As shown in FIG. 8, memory830 configures the processor 820 to implement one or more methods,steps, and functions (collectively, shown as process 880 in FIG. 8). Thememory 830 could be distributed or local and the processor 820 could bedistributed or singular. Different steps could be carried out bydifferent processors.

The memory 830 could be implemented as an electrical, magnetic oroptical memory, or any combination of these or other types of storagedevices. It should be noted that if distributed processors are employed,each distributed processor that makes up processor 820 generallycontains its own addressable memory space. It should also be noted thatsome or all of computer system 800 can be incorporated into anapplication-specific or general-use integrated circuit. For example, oneor more method steps could be implemented in hardware in an ASIC ratherthan using firmware. Display 840 is representative of a variety ofpossible input/output devices (e.g., keyboards, mice, and the like).Every processor may not have a display, keyboard, mouse or the likeassociated with it.

As is known in the art, part or all of one or more aspects of themethods and apparatus discussed herein may be distributed as an articleof manufacture that itself includes a tangible computer readablerecordable storage medium having computer readable code means embodiedthereon. The computer readable program code means is operable, inconjunction with a computer system (including, for example, system 800or processing capability on a firewall, intrusion prevention system, orthe like), to carry out all or some of the steps to perform the methodsor create the apparatuses discussed herein. A computer readable mediummay, in general, be a recordable medium (e.g., floppy disks, harddrives, compact disks, EEPROMs, or memory cards) or may be atransmission medium (e.g., a network including fiber-optics, theworld-wide web, cables, or a wireless channel using time-divisionmultiple access, code-division multiple access, or other radio-frequencychannel). Any medium known or developed that can store informationsuitable for use with a computer system may be used. Thecomputer-readable code means is any mechanism for allowing a computer toread instructions and data, such as magnetic variations on a magneticmedium or height variations on the surface of a compact disk. The mediumcan be distributed on multiple physical devices (or over multiplenetworks). As used herein, a tangible computer-readable recordablestorage medium is defined to encompass a recordable medium, examples ofwhich are set forth above, but is defined not to encompass atransmission medium or disembodied signal.

The computer systems and servers and other pertinent elements describedherein each typically contain a memory that will configure associatedprocessors to implement the methods, steps, and functions disclosedherein. The memories could be distributed or local and the processorscould be distributed or singular. The memories could be implemented asan electrical, magnetic or optical memory, or any combination of theseor other types of storage devices. Moreover, the term “memory” should beconstrued broadly enough to encompass any information able to be readfrom or written to an address in the addressable space accessed by anassociated processor. With this definition, information on a network isstill within a memory because the associated processor can retrieve theinformation from the network.

Accordingly, it will be appreciated that one or more embodiments of thepresent invention can include a computer program comprising computerprogram code means adapted to perform one or all of the steps of anymethods or claims set forth herein when such program is run, forexample, on a server implementing one or more of blocks 708, 710, 712,714, and the like, and that such program may be embodied on a tangiblecomputer readable recordable storage medium.

As used herein, including the claims, a “server” includes a physicaldata processing system (for example, system 800 as shown in FIG. 8)running a server program. It will be understood that such a physicalserver may or may not include a display, keyboard, or other input/outputcomponents. Furthermore, as used herein, including the claims, a“router” includes a networking device with both software and hardwaretailored to the tasks of routing and forwarding information.

Furthermore, it should be noted that any of the methods described hereincan include an additional step of providing a system comprising distinctsoftware modules embodied on one or more tangible computer readablestorage media. All the modules (or any subset thereof) can be on thesame medium, or each can be on a different medium, for example. Themodules can include any or all of the components shown in the figures(e.g. modules to implement blocks 708, 710, 712, 714). The method stepscan then be carried out using the distinct software modules of thesystem, executing on one or more hardware processors. Further, acomputer program product can include a tangible computer-readablerecordable storage medium with code adapted to be executed to carry outone or more method steps described herein, including the provision ofthe system with the distinct software modules. Referring again to FIG.9, in some instances, topology map engine 712 includes lease requestreceiver module 791, interrogator module 793, optionally schedulermodule 795, and change determining module 797. Each of 791-797 can beimplemented as distinct software modules (or sub-modules of module 712)embodied on one or more tangible computer readable storage media as justdescribed.

Accordingly, it will be appreciated that one or more embodiments of theinvention can include a computer program including computer program codemeans adapted to perform one or all of the steps of any methods orclaims set forth herein when such program is implemented on a processor,and that such program may be embodied on a tangible computer readablerecordable storage medium. Further, one or more embodiments of thepresent invention can include a processor including code adapted tocause the processor to carry out one or more steps of methods or claimsset forth herein, together with one or more apparatus elements orfeatures as depicted and described herein.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various other changes and modifications may bemade by one skilled in the art without departing from the scope orspirit of the invention.

What is claimed is:
 1. A method comprising the steps of: obtaining, at atopology map engine, from a dynamic host control protocol relay device,via a lease forwarder on a dynamic host control protocol serverdownstream of the topology map engine and upstream of the dynamic hostcontrol protocol relay device, a relayed request, of a client, for adynamic host control protocol lease, said relayed request having atleast one given internet protocol address of said dynamic host controlprotocol relay device inserted therein; searching, in a databasecollocated with said topology map engine, for said at least one giveninternet protocol address of said dynamic host control protocol relaydevice; if said at least one given internet protocol address of saiddynamic host control protocol relay device is not found in said databasein said searching step, performing an automated process to discover eachof one or more internet protocol subnets configured on said dynamic hostcontrol protocol relay device, said process comprising the steps of:obtaining, at said topology map engine, from said dynamic host controlprotocol relay device, dynamic host control protocol relay deviceinformation comprising at least: an identifier of said dynamic hostcontrol protocol relay device, said identifier of said dynamic hostprotocol relay device being distinct from said at least one giveninternet protocol address of said dynamic host control protocol relaydevice inserted in said relayed request; and at least one networkinterface of said dynamic host control protocol relay device and anyinternet protocol address assigned to said at least one networkinterface of said dynamic host control protocol relay device; andstoring said dynamic host control protocol relay device information insaid database.
 2. The method of claim 1, wherein in said step ofobtaining said dynamic host control protocol relay device information,said identifier comprises a permanent identifier.
 3. The method of claim2, further comprising: if said at least one given internet protocoladdress of said dynamic host control protocol relay device is not foundin said database in said searching step, sending a query, from saidtopology map engine, back to said dynamic host control protocol relaydevice, for said dynamic host control protocol relay device information;wherein said dynamic host control protocol relay device informationcomprises: said permanent identifier of said dynamic host controlprotocol relay device; all network interfaces of said dynamic hostcontrol protocol relay device; and all internet protocol addresses,including said at least one given internet protocol address, assigned tosaid network interfaces of said dynamic host control protocol relaydevice.
 4. The method of claim 3, wherein, in said step of obtainingsaid relayed request, said relayed request comprises an InternetProtocol Version 6 (IPv6) request.
 5. The method of claim 4, furthercomprising repeating said steps of obtaining said relayed request,searching in said database, sending said query, obtaining said dynamichost control protocol relay device information, and storing said dynamichost control protocol relay device information, for an additionalrelayed request, said additional relayed request comprising an InternetProtocol Version 4 (IPv4) request.
 6. The method of claim 3, furthercomprising: repeating said steps of obtaining said relayed request, andsearching in said database, for a relayed request from another, known,dynamic host control protocol relay device relaying a request of anotherclient; responsive to at least one given internet protocol address ofsaid known dynamic host control protocol relay device being found insaid database in said repeated searching step, searching said databasefor a subnet containing an address of said another client.
 7. The methodof claim 6, further comprising, responsive to said subnet not beingfound in said database, rediscovering said known, dynamic host controlprotocol relay device.
 8. The method of claim 3, wherein said sending ofsaid query, from said topology map engine, back to said dynamic hostcontrol protocol relay device, for said dynamic host control protocolrelay device information, comprises sending said query as a simplenetwork management protocol message.
 9. The method of claim 3, wherein,in said step of obtaining said relayed request, said relayed requestcomprises an Internet Protocol Version 4 (IPv4) request.
 10. The methodof claim 3, wherein, in said steps of sending said query and obtainingsaid dynamic host control protocol relay device information, saidpermanent identifier of said dynamic host control protocol relay devicecomprises a hostname.
 11. The method of claim 3, wherein, in said stepsof sending said query and obtaining said dynamic host control protocolrelay device information, said permanent identifier of said dynamic hostcontrol protocol relay device comprises a serial number.
 12. The methodof claim 3, wherein, in said steps of sending said query and obtainingsaid dynamic host control protocol relay device information, saidpermanent identifier of said dynamic host control protocol relay devicecomprises a loopback internet protocol address.
 13. The method of claim3, wherein, in said steps of obtaining said relayed request, sendingsaid query, and obtaining said dynamic host control protocol relaydevice information, said dynamic host control protocol relay devicecomprises a cable modem termination system.
 14. The method of claim 3,wherein, in said steps of obtaining said relayed request, sending saidquery, and obtaining said dynamic host control protocol relay deviceinformation, said dynamic host control protocol relay device comprises adigital subscriber line access multiplexer.
 15. The method of claim 3,further comprising: repeating said steps of obtaining said relayedrequest, searching in said database, sending said query, obtaining saiddynamic host control protocol relay device information, and storing saiddynamic host control protocol relay device information, for a pluralityof additional relayed requests from a plurality of additional dynamichost control protocol relay devices; and based on said repeated steps,maintaining a historical log.
 16. The method of claim 3, wherein, insaid steps of querying for and obtaining said dynamic host controlprotocol relay information, said internet protocol addresses assigned tosaid network interfaces of said dynamic host control protocol relaydevice comprise said at least one given internet protocol address, andat least one additional statically allocated internet protocol address.17. The method of claim 3, wherein: said obtaining of said relayedrequest is carried out by a lease request receiver module, embodied on anon-transitory computer readable medium, executing on at least onehardware processor; said searching in said database is carried out bysaid lease request receiver module executing on said at least onehardware processor; said sending of said query is carried out by aninterrogator module, embodied on said non-transitory computer readablemedium, executing on said at least one hardware processor; saidobtaining of said dynamic host control protocol relay device informationis carried out by said lease request receiver module executing on saidat least one hardware processor; and said storing of said dynamic hostcontrol protocol relay device information in said database is carriedout by said lease request receiver module executing on said at least onehardware processor.
 18. A method comprising the steps of: obtaining, ata topology map engine, from a dynamic host control protocol relaydevice, a relayed request, of a client, for a dynamic host controlprotocol lease, said relayed request having at least one given internetprotocol address of said dynamic host control protocol relay deviceinserted therein; searching, in a database, for said at least one giveninternet protocol address of said dynamic host control protocol relaydevice; if said at least one given internet protocol address of saiddynamic host control protocol relay device is not found in said databasein said searching step, obtaining, at said topology map engine, fromsaid dynamic host control protocol relay device, dynamic host controlprotocol relay device information comprising at least: an identifier ofsaid dynamic host control protocol relay device; and at least onenetwork interface of said dynamic host control protocol relay device andany internet protocol address assigned to said at least one networkinterface of said dynamic host control protocol relay device; storingsaid dynamic host control protocol relay device information in saiddatabase; and if said at least one given internet protocol address ofsaid dynamic host control protocol relay device is not found in saiddatabase in said searching step, sending a query, from said topology mapengine, back to said dynamic host control protocol relay device, forsaid dynamic host control protocol relay device information; wherein insaid step of obtaining said dynamic host control protocol relay deviceinformation, said identifier comprises a permanent identifier; whereinsaid dynamic host control protocol relay device information comprises:said permanent identifier of said dynamic host control protocol relaydevice; all network interfaces of said dynamic host control protocolrelay device; and all internet protocol addresses, including said atleast one given internet protocol address, assigned to said networkinterfaces of said dynamic host control protocol relay device; andwherein, in said steps of sending said query and obtaining said dynamichost control protocol relay device information, said permanentidentifier of said dynamic host control protocol relay device comprisesa loopback internet protocol address.
 19. The method of claim 18,wherein, in said obtaining and searching steps, said database and saidtopology map engine are collocated in a data center.
 20. A methodcomprising the steps of: obtaining, at a topology map engine, from adynamic host control protocol relay device, a relayed request, of aclient, for a dynamic host control protocol lease, said relayed requesthaving at least one given internet protocol address of said dynamic hostcontrol protocol relay device inserted therein; searching, in adatabase, for said at least one given internet protocol address of saiddynamic host control protocol relay device; if said at least one giveninternet protocol address of said dynamic host control protocol relaydevice is not found in said database in said searching step, obtaining,at said topology map engine, from said dynamic host control protocolrelay device, dynamic host control protocol relay device informationcomprising at least: an identifier of said dynamic host control protocolrelay device; and at least one network interface of said dynamic hostcontrol protocol relay device and any internet protocol address assignedto said at least one network interface of said dynamic host controlprotocol relay device; storing said dynamic host control protocol relaydevice information in said database; and if said at least one giveninternet protocol address of said dynamic host control protocol relaydevice is not found in said database in said searching step, sending aquery, from said topology map engine, back to said dynamic host controlprotocol relay device, for said dynamic host control protocol relaydevice information; wherein in said step of obtaining said dynamic hostcontrol protocol relay device information, said identifier comprises apermanent identifier; wherein said dynamic host control protocol relaydevice information comprises: said permanent identifier of said dynamichost control protocol relay device; all network interfaces of saiddynamic host control protocol relay device; and all internet protocoladdresses, including said at least one given internet protocol address,assigned to said network interfaces of said dynamic host controlprotocol relay device; and wherein, in said steps of querying for andobtaining said dynamic host control protocol relay information, saidinternet protocol addresses assigned to said network interfaces of saiddynamic host control protocol relay device comprise said at least onegiven internet protocol address, and at least one additional staticallyallocated internet protocol address.
 21. The method of claim 20,wherein, in said obtaining and searching steps, said database and saidtopology map engine are collocated in a data center.